Sign up at /auth (Google or email magic link), then pick a username at complete-registration. You get 500 free credits one time. See Sign-in, account & public pages.
Create an organization: go to /onboarding/org, enter a name and pick a type (Agency / Studio / School / University / Other), then create it. You become the org admin. (Or accept an invite link at /invite/{token} to join an existing org.) See Plans, credits & organizations.
Start generating: open the editor, type a prompt in the chat bar with the category on Image, and send. Switch the category pill to Video or 3D for other outputs. See Chat bar: generating images.